Explanation:
The beat is a word used for sound waves. The beat frequency is the difference in frequency of two waves. ... In sound, we hear said beat frequency as the rate at which the loudness of the sound varies whereas we hear the ordinary frequency of the waves as the pitch of the sound.
Answer:
Option B, to establish the reference polarity for induced voltages
Explanation:
Dot basically indicates the polarity of the electrical windings. Currents entering and leaving the same dotted ends will produce magnetic flux in same direction while the current entering at one dotted end and leaving at another dotted end will produce opposing magnetic flux.
Thus it is clear that dot represents the terminals having same phases of induced AC voltages so that only one winding is loaded at a time.
Hence, option B is correct
Xenon is #54 on the periodic table
Answer:
The thermal conductivity ![k = 1.4094 W/ m\cdot K](https://tex.z-dn.net/?f=k%20%20%3D%201.4094%20%20%20W%2F%20m%5Ccdot%20K)
Explanation:
From the question we are told that
The depth of the thermocouple from the surface is x = 10 mm = 0.01 m
The temperature is ![T_f = 100 ^o C](https://tex.z-dn.net/?f=T_f%20%20%3D%20%20100%20%5Eo%20C)
The initial temperature is ![T_i = 30 ^o C](https://tex.z-dn.net/?f=T_i%20%20%3D%20%2030%20%5Eo%20C)
The temperature of the thermocouple after t = 2 minutes( 2 * 60 = 120 \ seconds) is ![T_t = 65 ^o C](https://tex.z-dn.net/?f=T_t%20%20%3D%20%2065%20%5Eo%20C)
The density of the material is ![\rho = 2200 kg/m^3](https://tex.z-dn.net/?f=%5Crho%20%3D%20%202200%20kg%2Fm%5E3)
The specific heat of the solid ![c_s = 700 J/kg \cdot K](https://tex.z-dn.net/?f=c_s%20%20%3D%20%20700%20J%2Fkg%20%5Ccdot%20K)
Generally the equation for semi -infinite medium is mathematically as
![\frac{T_s - T }{T_i - T} = erf [\frac{x}{2 \sqrt{\alpha * t} } ]](https://tex.z-dn.net/?f=%5Cfrac%7BT_s%20-%20T%20%7D%7BT_i%20-%20T%7D%20%3D%20%20erf%20%5B%5Cfrac%7Bx%7D%7B2%20%5Csqrt%7B%5Calpha%20%20%2A%20t%7D%20%7D%20%5D)
![\frac{65 - 100 }{30 - 100} = erf [\frac{x}{2 \sqrt{\alpha * t} } ]](https://tex.z-dn.net/?f=%5Cfrac%7B65%20-%20100%20%7D%7B30%20-%20100%7D%20%3D%20%20erf%20%5B%5Cfrac%7Bx%7D%7B2%20%5Csqrt%7B%5Calpha%20%20%2A%20t%7D%20%7D%20%5D)
![0.5 = erf [\frac{0.01}{2 \sqrt{\alpha * 120} } ]](https://tex.z-dn.net/?f=0.5%20%3D%20%20erf%20%5B%5Cfrac%7B0.01%7D%7B2%20%5Csqrt%7B%5Calpha%20%20%2A%20120%7D%20%7D%20%5D)
Here
is a constant with unit ![m^2 /s](https://tex.z-dn.net/?f=m%5E2%20%2Fs)
this is from the Gaussian function table
![0.0 1 = 0.954 * (\sqrt{\alpha * 120 } )](https://tex.z-dn.net/?f=0.0%201%20%3D%20%200.954%20%2A%20%28%5Csqrt%7B%5Calpha%20%2A%20120%20%20%7D%20%29)
=> ![\sqrt{\alpha * 120 } = \frac{0.01 }{0.954 }](https://tex.z-dn.net/?f=%5Csqrt%7B%5Calpha%20%20%2A%20120%20%20%7D%20%3D%20%20%5Cfrac%7B0.01%20%7D%7B0.954%20%7D)
=> ![\alpha = 9.1525 *10^{-7} \ m^2 /s](https://tex.z-dn.net/?f=%5Calpha%20%3D%20%209.1525%20%2A10%5E%7B-7%7D%20%5C%20%20m%5E2%20%2Fs)
Generally the thermal conductivity is mathematically represented as
![k = \alpha * \rho * c_s](https://tex.z-dn.net/?f=k%20%20%3D%20%20%5Calpha%20%20%2A%20%20%5Crho%20%2A%20c_s)
![k = 9.1525 *10^{-7} * 2200 * 700](https://tex.z-dn.net/?f=k%20%20%3D%209.1525%20%2A10%5E%7B-7%7D%20%20%20%2A%20%202200%20%2A%20700)
![k = 1.4094 W/ m\cdot K](https://tex.z-dn.net/?f=k%20%20%3D%201.4094%20%20%20W%2F%20m%5Ccdot%20K)
The correct choice is Buffers.
Buffers contains both acids and bases in equilibrium.when base is added to buffers, they adjust the pH value by releasing hydrogen ions.when acid is added to buffers, they adjust the pH value by consuming hydrogen ions. hence these substances resist any change in their pH value by releasing or absorbing hydrogen ions.This process keeps the pH value constant.